| Objective: To screen the cases of intrauterine infection(IAI)by placental pathology examination,and to investigate the relationship between neonatal respiratory distress syndrome(NRDS),bronchopulmonary dysplasia(BPD)and exposure to IAI in premature infants under 32 weeks of gestational age,and the relationship between placental pathological stages of IAI and the severity of NRDS and BPD.Methods: From July 2018 to June 2020,332 premature infants who were born in the obstetrics department of Qingdao Women’s and Children’s Hospital with a gestational age of less than 32 weeks and were transferred to the NICU within 24 hours of birth were selected.According to the results of placental examination,infants were divided into the IAI group and control group.Among them,there were 231 infants in the IAI group and 101 in the control group.According to previous research,collect and analyze prenatal and postnatal data that may be related to the occurrence of NRDS and BPD.The data of the IAI group and the control group were compared to explore the influence of IAI on the occurrence of NRDS and BPD in preterm infants less than 32 weeks of gestational age,and the relationship between the pathological stage of the placenta and the severity of NRDS and BPD.Results: 1.There were no significant differences in maternal age,proportion of primiparas,singleton rate,combined diabetes mellitus,premature rupture of membranes,placental abruption rate,prenatal glucocorticoid utilization rate,and incidence of intrauterine distress between the two groups(P>0.05).The prenatal antibiotic use rate of mothers in the IAI group was 60.2%(139/231),which was significantly higher than the 48.5%(49/101)of the control group(P<0.05).2.There were no significant differences in gestational age,gender,birth weight,birth asphyxia rate,1 min Apgar score,5 min Apgar score,Pa O2,Pa CO2,and lactic acid between the two groups(P>0.05).3.The prenatal WBC and CRP>0.8mg/L rates of mothers in the IAI group were significantly higher than those in the control group,and the WBC and CRP>0.8mg/L rates of infants in the IAI group were significantly higher than those in the control group(P<0.05).There was no significant difference in PCT between the two groups(P>0.05).4.The incidence of BPD in the IAI group was 40.3%(93/231),which was significantly higher than the 26.7%(27/101)of the control group(P<0.05).The incidence of NRDS in the IAI group was 29.0%(67/231),which was significantly lower than 45.5%(46/101)in the control group(P<0.05).5.In 67 newborns with NRDS,correlation analysis showed no correlation between IAI placental pathological stage and NRDS grade(rs=-0.045,P=0.720).In 93 preterm infants diagnosed with BPD,correlation analysis showed no correlation between IAI placental pathological stage and BPD grading(rs =0.052,P=0.621).6.There were no significant differences in tracheal intubation rate,duration of invasive ventilation,maximum oxygen concentration,non-invasive ventilation rate,duration of non-invasive ventilation,and duration of oxygen inhalation between the two groups(P>0.05).The usage rate of PS in the IAI group was 25.5%(59/231),which was significantly lower than 41.6%(42/101)in the control group(P<0.05).Conclusion: 1.IAI is closely related to the occurrence of NRDS and BPD in infants with gestational age less than 32 weeks.Preterm infants born to IAI mothers had a high incidence of BPD and a low incidence of NRDS.2.The placental pathological stage of IAI may not be associated with NRDS grade and BPD grade of preterm infants with gestational age less than 32 weeks.3.The mother’s WBC and CRP increase before delivery,and the increase of WBC and CRP within 24 h after birth may be related to the occurrence of IAI.Objective: 1.To establish an IAI model with LPS and observe the effect of LPS on placental inflammation in pregnant rats.2.The survival rate,body weight,lung weight,and pathological changes of lung tissue of newborn rats born from IAI rats were observed,and the expression of NOD-like receptor protein 3(NLRP3)and matrix metalloproteinase-9(MMP-9)in lung tissues were detected.3.Observe the effect of glibenclamide on placental inflammation in IAI rats and the changes of the above indicators in newborn rats,and explore the effect of glibenclamide on IAI and lung injury in newborn rats.Methods: 1.Experimental grouping: 24 pregnant rats were selected and randomly divided into control group,LPS group(LPS intervention),and treatment group(LPS + glibenclamide intervention),each group had 8 pregnant rats.2.IAI model making and glibenclamide intervention: pregnant rats in the LPS group and treatment group were injected intraperitoneally with 0.5 mg/kg LPS once at the 18 th gestational age,and the pregnant rats in the control group were injected with the same dose of solvent at the same time.The pregnant rats in the treatment group were given 1 mg/kg glibenclamide suspension once 12 hours after LPS injection,and repeated once at the 19 th and 20 th day of gestation.The pregnant rats in the control group and the LPS group were given the same amount of solvent intragastric infusion at the same time.3.Specimen collection: One pregnant rat was randomly selected from each group at 21 days of gestation,and placental tissue was collected and fixed in formaldehyde after anesthesia.The remaining pregnant rats were delivered naturally,and the newborn rats were sacrificed on day 1,7,and 14 respectively,and the lobe of left lung was taken for HE staining or immunohistochemical staining.4.Observation of indicators: Blood glucose level was detected by caudal venipuncture before and 1h after gavage in each pregnant rat,and one newborn rat born from each pregnant rat was randomly selected for blood glucose detection after delivery.The pathological changes of the placenta of pregnant rats were observed,and the level of NLRP3 was detected by DAB staining.Observe the death and miscarriage of pregnant rats,observe the number and survival of newborn rats.The bodyweight of neonatal rats was weighed before executed on the 1st,7th,and 14 th day after birth,and the lung weight was weighed after executed to calculate the value of lung weight/body weight.The thickness of the alveolar septum was observed on the 1st,7th and 14 th days after birth,the radial alveolar count(RAC)was observed on the 7th and 14 th days,and the levels of NLRP3 and MMP-9 in lung tissue were detected by DAB staining on the 1st and 7th days.Results: 1.There was no death or miscarriage in all the pregnant rats.76 newborn rats in the control group survived,the survival rate was 100%.In the LPS group,73 newborn rats were delivered,and 70 survived,the survival rate was 95.9%.In the treatment group,74 newborn rats survived,the survival rate was 100%.2.The placenta in the LPS group was infiltrated with a large number of neutrophils,congestion and edema were obvious,the placenta structure was disordered,and a large number of NLRP3 chemical staining positive cells were seen.The placenta structure of the control group was clear,no inflammatory cells were observed,and NLRP3 chemical staining showed no positive cells.There were a few inflammatory cells in the placenta of the treatment group,and the degree of congestion and edema was mild,and NLRP3 chemical staining showed some positive cells.3.No hypoglycemia was detected before and after intragastric administration in pregnant rats and neonatal rats in each group.4.There was no significant difference in the weight of neonatal rats in each group at the same time(P>0.05).5.The lung weight of newborn rats in the LPS group on the first day after birth was significantly lower than that of the control group and the treatment group(P<0.0167).There was no significant difference in the lung weight of neonatal rats between the control group and the treatment group on the 1st day after birth(P<0.0167).There was no significant difference in the lung weight between the three groups on the 7th and 14 th day after birth(P>0.05).6.The lung weight/body weight of neonatal rats in the LPS group on the first day after birth was significantly lower than that in the control group and the treatment group(P<0.0167).There was no significant difference in the lung weight/body weight between the control group and the treatment group on the 1st day after birth(P<0.0167).There was no significant difference in the lung weight/body weight among the three groups on the 7th and 14 th day(P>0.05).7.With the increase of neonatal age,the alveolar septum in the control group significantly thinned,the alveolar septum in the LPS group slightly thickened,and the alveolar septum in the treatment group slightly thinned.8.There was no significant difference in RAC between the three groups on the 7th day after birth(P>0.05),and the difference between the control group and the treatment group on the 14 th day after birth was no significant(P>0.0167).The RAC of neonatal mice in the LPS group was significantly lower than that in the control group and treatment group at 14 postnatal days(P<0.0167).9.On the first day after birth,the NLRP3 level of newborn rats in the LPS group was significantly higher than that of the control group,and on the 7th day after birth,the NLRP3 level of the newborn rats in the LPS group was significantly higher than that of the control and treatment groups(P<0.0167).MMP-9 levels in lung tissue of newborn rats in the LPS group and treatment group were significantly higher than those in the control group on the first day after birth,and MMP-9 levels in lung tissue of the newborn rats in the LPS group were significantly higher than those in the control group and treatment group on the 7th day after birth(P<0.0167).There was no significant difference in lung tissue NLRP3 or MMP-9 between other two groups of newborn rats on the 1st or 7th day after birth(P>0.0167).Conclusion: 1.IAI can affect the development of fetal rat lung tissue in utero,resulting in lung injury and lung development in neonatal rat.In the 14 days after birth,the alveolar septum was gradually thickened and the formation of alveoli decreased.2.Intragastric infusion of glibenclamide in the third trimester of pregnancy in IAI pregnant rats can reduce the inflammation of the placenta,reduce the levels of NLRP3 and MMP-9 in the lung tissue of newborn rats,reduce lung injury,and improve the development of lung tissue,confirmed that the NLRP3 inflammatory corpuscle and MMP-9 in newborn rat lung injury caused by IAI play an important role. |
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